簡單工廠設計模式C++實作

簡單工廠設計模式            

C++代碼：

    電腦加減乘除功能實作

    計算抽象類及其具體實作各子類定義與實作：

Operator.h定義：

#ifndef OPERATOR_H
#define OPERATOR_H

#include <iostream>
#include <string>
using namespace std;
class Operator
{
   public:
	   double NumberA;
	   double NumberB;
   public:
	    virtual double GetResult()
		{
			double result=0;
			return result;
		}
};

class OperatorAdd:public Operator
{
	double GetResult();
};
class OperatorSub:public Operator
{
	double GetResult();
};
class OperatorMul:public Operator
{
	double GetResult();
};
class OperatorDiv:public Operator
{
	double GetResult();
};
#endif
           

實作：

#include "Operator.h"

double OperatorAdd::GetResult()
{
	return NumberA+NumberB;
}
double OperatorSub::GetResult()
{
	return NumberA-NumberB;
}
double OperatorMul::GetResult()
{
	return NumberA*NumberB;
}
double OperatorDiv::GetResult()
{
	if(NumberB!=0)
	  return NumberA/NumberB;
	else
	   cout << "NumberB can't be 0!" << endl;
}
           

簡單工廠類定義及實作（SimpleFactory.h）

#ifndef SIMPLEFACTORY_H
#define SIMPLEFACTORY_H
#include "Operator.h"

class SimpleFactory
{
public:
	static Operator * CreateFactory(char operate)
	{
		Operator *oper = NULL;
		switch(operate)
		{
		  case '+':
			  oper = new OperatorAdd();
			  break;
           case '-':
			  oper = new OperatorSub();
			  break;
           case '*':
			  oper = new OperatorMul();
			  break;
		   case '/':
			  oper = new OperatorDiv();
			  break;

		}	
		return oper;

	}
};
#endif
           

用戶端代碼：

#include "SimpleFactory.h"

int main()
{
	Operator * op=SimpleFactory.CreateFactory('+');
	op->NumberA=1;
	op->NumberB=2;
	cout << op->GetResult() << endl;

	delete op;
	return 0;
}